Rc1: Cleaned jpg increased file size.

[Taboc]

Some jpg increase file size when Clean:Optimize huffman table is unchecked.

http://img64.imageshack.us/img64/3416/13kz1.jpg
http://img64.imageshack.us/img64/7514/22ju1.jpg

XnView 1.82 -

[Xyzzy]

Yes, there is something wrong about Clean.

Files with no EXIF/IPTC data grow after they are cleaned with EXIF/IPTC related options checked.

X.

[xnview]

Some jpg increase file size when Clean:Optimize huffman table is unchecked.

Seems to be correct All other software with a clean feature have this behaviour...

[Dreamer]

Some jpg increase file size when Clean:Optimize huffman table is unchecked.

Seems to be correct All other software with a clean feature have this behaviour...

So close?

[Clo]

Hello !

Seems to be correct All other softwares with a clean feature have this behaviour…

… that doesn't mean it's normal and logical…

- I tested with the image below, and got a small gain at size, ~4KB less…

—————

- Please, could you check whether you get the same ?
{ BTW : the caption on the pic tells «I've also MY anti-virus }

Kind regards,
Claude'
Clo

[FlorianH]

- Please, could you check whether you get the same ?

I can confirm:

a) original file 58.191 bytes
b) original file cleaned with all options except optimize -> 58.191 bytes (same size)
c) original file cleaned with all options (incl. optimize) -> 54.259 bytes
d) file c) cleaned with all options except optimize -> 58.191 bytes strange!

I think from the technical point of view (pierre's view?), behaviour b) is ok. But behaviour d) is not realy easy to explain...

[Dreamer]

Moved back to New/Open, since it's still not clear if current behavior is standard or not.

[xnview]

Moved back to New/Open, since it's still not clear if current behavior is standard or not.

There is no bug here

[Olivier_G]

Seems strange that removing data actually increase filesize...
-> can't you actually remove the corresponding metadata space completely ?

[xnview]

Seems strange that removing data actually increase filesize...
-> can't you actually remove the corresponding metadata space completely ?

Metadata is removed, but i think that huffmann code is rearranged.

[Xyzzy]

Seems strange that removing data actually increase filesize...
-> can't you actually remove the corresponding metadata space completely ?

Metadata is removed, but i think that huffmann code is rearranged.

OK, I think this solves the puzzle. But is there any need to NOT optimize Huffman tree?

X.

[Olivier_G]

More tests:
I converted a TIFF to JPEG (no Huff Optimization) -> image without metadata: 323644 B
I added several IPTC&Comments -> 323977 B
I cleaned those metadata (no Huff Optimize) -> 323644 B
=> back to original size without metadata (optimize Huff gives 320305 B).

It looks fine to me regarding the way metadata are handled.
(and also regarding Huffman table optimization)

Olivier

[Xyzzy]

OK, I think this solves the puzzle. But is there any need to NOT optimize Huffman tree?

Self-reply

Yes, when there is image with already optimized coding (fe. by some specialized packer)- applying Huffman could grow it. Looking at Olivier_G test it can be Closed, right?

X.